The inert rendering of a storage container consists of replacing the air existing in the storage container with an inert gas. The inert-rendering is, in particular, employed for the storage of inflammable products, for the storage of products which degrade in contact with the oxygen in the air, or even for reactions under an inert atmosphere. In order to render a storage container inert, it is possible to employ various methods, for example a method of pressurization/depressurization or of scavenging by the chosen inert gas. These methods enable the concentration of oxygen in the storage container to be gradually lowered.
The pressure of the inert gas in the storage container is called "inert-rendering pressure". Generally, this pressure is slightly greater than ambient pressure, so that leaks between the storage container and ambient atmosphere do not lead to a decrease in the quality of the inert-rendering.
The problem which the invention is provided to solve is that of maintaining the inert-rendering pressure. In fact, during the use of the storage container and once inert-rendering has been achieved (for example by pressurization/depressurization), manifold factors tend to cause the inert-rendering pressure to decrease. Leading off the product held in the storage container decreases the inert-rendering pressure. Temperature variations of the walls of the storage container may have the same effect. It is therefore necessary to maintain the inert-rendering pressure at its rated value.